How to selectively delete from TList

invarbrass · Hält's aus hier Beiträge: 4

I have a snippet of code that iterates through a TList and deletes some items. The code is as follows:

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procedure PurgeList;
var
  P: PSomeRecord;
  I: Integer;
begin
  I := 0;
  while (I < FList.Count) do  
  begin
    P := PSomeRecord(FList[I]);
    if P^.CanDelete then
    begin
      FreeMem(P);
      P := nil;
      FList.Delete(I);
      Continue;
    end;
    Inc(I);
  end;
end;

Is this the right way to delete items from a tlist? or will it enter into an infinite loop?
can anyone show me any other way to remove items from a tlist?
thanks in advance

hazard999 · Verfasst: Di 29.04.08 07:22

Hi,

your source isn't wrong at all.

But you've to count downto 0.

If you're counting upwards you will leave every item after a delete untouched.

r u

René

_________________
MOV EAX, Result;MOV BYTE PTR [EAX], $B9;MOV ECX, M.Data;MOV DWORD PTR [EAX+$1], ECX;MOV BYTE PTR [EAX+$5], $5A;MOV BYTE PTR [EAX+$6], $51;MOV BYTE PTR [EAX+$7], $52;MOV BYTE PTR [EAX+$8], $B9;MOV ECX, M.Code;MOV DWORD PTR [EAX+$9], ECX

Narses · Verfasst: Di 29.04.08 07:24

Hi!

I would suggest this:

markieren

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procedure PurgeList;
  var
    P: PSomeRecord;
    i: Integer;
begin
  for i := FList.Count-1 downto 0 do begin
    P := PSomeRecord(FList.Items[i]);
    if (P^.CanDelete) then begin
      FreeMem(P);
      FList.Delete(i);
    end;
  end;
end;

cu
Narses

_________________
There are 10 types of people - those who understand binary and those who don´t.

invarbrass · Hält's aus hier Beiträge: 4

thanks for the ideas. much appreciated. i've updated my code according to your suggestions.

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